Bringing PowerPC Book E processors to Linux
This paper presents the approach taken in
porting Linux to the first implementation of
a PowerPC Book E specification processor,
the PowerPC 440GP. Book E processors
have an MMU architecture that differs greatly from that of other processor architectures.
The approach we have taken currently for handling this MMU is described as well as the plan for handling the MMU in a more graceful
manner.
Also presented are the kernel implications of the growing need to support a larger than 32-bit physical address space on a native 32-bit address space architecture. The PPC440GP introduced some new challenges in this area, so the current method of handling PCI and other I/O devices above 4GB is described. We will futher discuss some possibilities for providing better kernel support of large address spaces on a 32-bit processor.
